Today, facsimile machines are becoming commonplace in many business offices. The new facsimile machines offer a variety of features which enhance their usefulness. One common feature of prior art facsimile machines enables the automatic reception of messages even when an addressee is not present. However, because anyone can read the received facsimile message, a security problem may exist when private or personal facsimile information is received.
U.S. Pat. No. 5,191,611 issued to G. S. Lang on Mar. 2, 1993 describes a method and apparatus for protecting material on storage media by limiting access to the storage medium. More specifically, the storage medium is divided into sectors and each sector is assigned to a specific user. Access to that sector of the storage medium can be gained only when the appropriate sequence of signals is executed. More particularly, Lang contemplates using a smart card as the device that a user will use to gain access to the storage medium. The smart card contains an encryption key and processing power, and the two combine to interact with the computer that guards the storage medium.
In one embodiment his invention, shown in FIG. 6 of the above-identified patent, Lang describes a facsimile apparatus (FIG. 6) for secure computerized fax (SCFAX) delivery. The sender loads a message/document to be transmitted, enters the sender's smart card, and enters the recipient's address. The recipient's fax machine is informed of the recipient's identity and that fax machine stores the information in the proper storage medium sector. In accordance with the above description, the storing of the fax data in a particular sector insures proper delivery.
In a more secure embodiment, the data itself is encrypted, either with a commonly known encryption key, or with the recipient's public key. The encryption is accomplished with the sender interfacing his/her smart card with the sending fax machine.
The problem with the Lang approach is that the recipient fax machine must know, before hand, of the identities of the people who will receive confidential faxes, so that the faxes can be stored in memory sectors associated with those people. In practice, the opposite is more likely. That is, a fax machine that is situated in a one-person office and communicates faxes to that individual does not need enhanced confidentiality, since no one else has access to the fax machine. A fax machine that is open to the public or is "semi-open" to the public, on the other hand, could greatly benefit from enhanced confidentiality but will not know, beforehand of the identity of those desiring to use the fax machine.